回顾Java组合内部类

简易计算器简化代码，组合
面向对象的写法
对象.

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

//简易计算机器
public class TextCalc {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算器类
class Calculator extends Frame{
    //属性
    TextField num1,num2,num3;
    //方法
    public void loadFrame(){
        num1 = new TextField(10);
        num2 = new TextField(10);
        num3 = new TextField(20);//字符数
        //1个标签
        Label label = new Label("+");
        //1个按钮
        Button button = new Button("=");
        button.addActionListener(new MyCalculatorListener(this));
        //布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        setVisible(true);
        pack();
    }

}
//***
class MyCalculatorListener implements ActionListener
{
    //获取计算器这个变量，在一个类中组合另外一个类
    Calculator calculator=null;
    private TextField num1,num2,num3;
        //把整个
    public MyCalculatorListener( Calculator calculator)
    {
            this.calculator=calculator;

    }
    @Override
    public void actionPerformed(ActionEvent e)
    {
        //1.获得加数和被加数
        int n1= Integer.parseInt(calculator.num1.getText());
        int n2= Integer.parseInt(calculator.num2.getText());//文本框内由string转换
        //加法运算后放到第三个框内
        calculator.num3.setText(""+(n1+n2));
        //清除前三个框
        calculator.num1.setText("");
        calculator.num2.setText("");
    }

}

内部类：

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

//简易计算机器
public class TextCalc {
    public static void main(String[] args) {
        new Calculator().loadFrame();
    }
}
//计算器类
class Calculator extends Frame{
    //属性
    TextField num1,num2,num3;
    //方法

    public void loadFrame() {
        num1 = new TextField(10);
        num2 = new TextField(10);
        num3 = new TextField(20);//字符数
        //1个标签
        Label label = new Label("+");
        //1个按钮
        Button button = new Button("=");
        button.addActionListener(new MyCalculatorListener());
        //布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        setVisible(true);
        pack();
    }
        //***类
    //内部类的好处就是可以畅通无阻的访问外部类
        private class MyCalculatorListener implements ActionListener
        {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                //1.获得加数和被加数
                int n1= Integer.parseInt(num1.getText());
                int n2= Integer.parseInt(num2.getText());//文本框内由string转换
                //加法运算后放到第三个框内
                num3.setText(""+(n1+n2));
                //清除前三个框
              num1.setText("");
             num2.setText("");
            }


    }

}